The data shows that, among the NEM states, only Queensland recorded an increase in consumption (0.15 per cent), while NSW, South Australia, Victoria and Tasmania all recorded decreases when compared with 2011.

It estimates that 2,000 GWh of the drop could be attributed to solar PV uptake and other strategies employed by Australian households and businesses to improve energy efficiency.

The mix of energy generation methods also continues to change.

GEM reports that renewables and scheduled gas grew their share of the market by 1.8 and 1.0 respectively, while coal-fired generation went from 80.9 per cent in 2011 to the reduced figure of 78 per cent in 2012.

As for the geographic spread of 2012's decrease, there was one clear winner.

Falling demand in NSW drove the national decrease, with electricity demand in the state dropping by 4,000 GWh (5.2 per cent).

Why such a big drop? GEM suggests that big factors could be the closure of the Kurri Kurri smelter and simply a milder winter.

The next biggest decrease was seen in Tasmania, where demand dropped by 3.7 per cent.